Magnetic Random Access Memory (MRAM) is a nonvolatile memory having a TMR element using a magnetoresistive effect (Tunneling Magneto Resistive: TMR) and has integration density similar to Dynamic Random Access Memory (DRAM) and a highspeed performance similar to Static Random Access Memory (SRAM), and the world pays attention to MRAM as a revolutionary next-generation memory in which data is rewritten repeatedly.
As the TMR element for MRAM, a perpendicular magnetization TMR element (hereinafter also referred to as a P-TMR element) suitable for high integration has been extensively used (see, Non-Patent Literature 1).
As a method of processing the TMR element, an ion beam etching (IBE) technique and a reactive ion etching (RIE) technique are used. It is known that processing is performed using an RIE method using a mixed gas of hydrocarbon and oxygen as an etching gas, for example, whereby a metal film in a magnetoresistive effect element can be selectively etched (see, Patent Literature 1).